There are no such things as "stupid" questions. However if you think your question is a bit stupid, then this is the right place for you to post it. Please stick to easy to-the-point questions that you feel people can answer fast. For long and complicated questions prefer the other forums within the support section. Before you post please read how to get help
Boot into "recovery mode" with the live cd, it will boot you to a terminal with root access without prompting for a password. Your partitions should be visible. Look in your /home folder on the partition in question and see what your username is. Then use the command "passwd userName" to set a new password.
"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke